Dental bur with liquid-cooled tip

ABSTRACT

According to the invention, there is provided an elongated liquid-cooled dental bur having a long direction, a proximal part adapted to be inserted into a drive device connected with a source of cooling fluid, a distal part having a cutting tip, a first channel in the proximal part fluidly communicating with the source of cooling fluid and at least one orifice extending from the first channel directed at the cutting tip for directing a spray of cooling liquid at the cutting tip, and further including a collar radially extending from the proximal part having a circumference, wherein the orifice is disposed in the collar proximal to the circumference, and wherein the collar has an end surface disposed transversely to the long direction facing the distal part, and the orifice is disposed in the end surface. The distal part is preferably removably secured to the collar, for removal and replacement of worn cutting tips. The distal part preferably fits into an axial bore in the collar and is secured in the axial bore with a set screw. The cutting tip may be substantially spherically shaped.

The invention relates to a dental bur adapted to be cooled with acooling liquid, and more particularly to a water-cooled dental burhaving an internal water channel terminating in a water dischargeaperture directing cooling water at the tip of the bur and having aremovable distal end.

BACKGROUND OF THE INVENTION

It is known that the process of drilling and cutting creates a greatdeal of heat where the dental cutting tool, known as a "bone bur", cutsinto the bone and causes dessication of the bone. The heat generated bythe bur causes dessication and destruction of the bone. It is thereforedesirable to apply cooling to the bur and the bone during the drillingand cutting process. It is also desirable for the bur to have a readilyremovable distal end so that the cutting tip can be inexpensivelyreplaced when worn.

It is known from the prior art to provide a water channel in a dentalbur, as shown in U.S. Pat. No. 3,393,452, which shows a dental burhaving a bore through its shank and through the cutting tip of the burextending to its distal end for admitting cooling water to the area ofthe tooth being drilled or cut. This arrangement, however, has thedrawback that it cannot be applied to dental burs of very smalldiameter, such as for example 1.3 mm or less, since practical technologyis not available for forming a long bore of such a small diameter. Bursof such small diameter are often required for drilling and cuttingteeth. U.S. Pat. No. 5,100,322 shows a water-cooled dental tool whichhas an internal hollow space and holes cut transversely through thecutting tip of the tool for admitting a stream of liquid or air forcooling the drilling operation. The dental bur according to the lastmentioned patent relies on only cooling liquid sprayed against theexterior of the cutting tool. The holes in the tool are, however, easilyfilled with cutting material from the tooth, so that the cooling actionis lost.

It is accordingly an object of the present invention to provide aliquid-cooled dental bur which does not have the drawbacks of the knowndental burs, and which provides effective cooling also for dental bursof quite small diameters.

It is a further object of the present invention to provide such a bur inwhich the cutting tip is easily removed and replaced.

Further objects and advantages of this invention will be apparent fromthe following detailed description of a presently preferred embodimentwhich is illustrated schematically in the accompanying drawings.

SUMMARY OF THE INVENTION

According to the invention, there is provided an elongated liquid-cooleddental bur having a long direction, a proximal part adapted to beinserted into a drive device connected with a source of cooling fluid, adistal part having a cutting tip, a channel in the proximal part fluidlycommunicating with the source of cooling fluid and at least one orificeextending from the channel directed at the cutting tip for directing aspray of cooling liquid at the cutting tip, and further including acollar radially extending from the proximal part having a circumference,wherein the orifice is disposed in the collar proximal to thecircumference, and wherein the collar has an end surface disposedtransversely to the long direction facing the distal part, and theorifice is disposed in the end surface.

According to a further feature the proximal end part is shaped as anelongate cylinder, and the channel is shaped as a central bore in thecylinder and the proximal end part has a facet substantially parallelwith the long direction for rotationally locking the bur in the drivedevice.

According to still another feature, the end part has a radial recess foraxially locking the bur in the drive device, and the bur tip has adiameter perpendicular to the long direction no greater than 1.3 mm.

As a still further feature, the cooling fluid is composed substantiallyof water.

As still another feature, the distal end of the bur is fit into an axialport in the body of the bur and removably secured with a set screw tomake the cutting tip readily replaceable. The cutting tip may besubstantially spherically shaped.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic, part cross-sectional view of a dental buraccording to the invention;

FIG. 2 is a fragmentary, part cross-sectional view of the central partof the dental bur according to the invention;

FIG. 3 is a cross-sectional view seen along the line 3--3 of FIG. 2; and

FIG. 4 is a fragmentary cross-section of the bur showing the area of thefluid aperture;

FIG. 5 is a diagrammatic, part cross-sectional view of a dental buraccording to the invention, illustrating how the bur distal end ispreferably removably secured in the body of the bur with a set screw andthe preferred spherical cutting tip.

Before explaining the disclosed embodiments of the present invention indetail it is to be understood that the invention is not limited in itsapplication to the details of the particular arrangements shown sincethe invention is capable of other embodiments. Also, the terminologyused herein is for the purpose of description and not of limitation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1 a dental bur generally at 1 is shown inserted in a drivedevice, generally at 2, shown in phantom lines. The drive device has aninternal central channel 3 which leads to a source of cooling liquidunder a given amount of pressure.

The dental bur 1 is elongated in a long direction indicated by adash-dot line A, and is composed of a proximal part 4 and a distal end11 having a cutting tip 12 no more than 1.3 mm in diameter with abrasiveor cutting surfaces. The proximal part is insertable in a drive device2, and has at its end 6 a facet 7, which is substantially parallel withthe long direction A. The facet 7 mates with a corresponding flatsurface in drive device 2 to provide a rotational lock on the bur 1.

The proximal part 6 also has an indentation or groove 8 which mates witha releasable latch 9 in the drive device 2, and provides axial lock ofthe dental bur. The middle proximal part 4 is advantageously ofcylindrical shape in which case the dash-dot line A indicates the axisof the bur 1.

The middle proximal part 4 expands at its end 13 facing away from thedrive device 2 into a collar 14 at a somewhat greater diameter of theproximal part 4. The proximal part 4 has an internal bore or channel 16which communicates at its proximal end with the central channel 3 of thedrive device 2. The channel 16 extends through the collar 14 anddeviates in the collar away from the axis A via a short channel section17 to communicate with an orifice 18 disposed proximal to thecircumference 19 of the collar 14, which in turn communicates with asmall spout or jet 21 which has an axis shown by the dash-dot line B,that is converging with the axis A at a point near the cutting tip 12,so as to direct a stream of cooling fluid ejected from the jet 21 at thecutting tip and the cutting area of the tooth being cut.

FIG. 2 shows in a cross-sectional enlarged view the details describedabove, including the channel 16 in the proximal part 4 and the collar14, which deviates as channel section 17 and communicates with theorifice 18 and the jet 21.

FIG. 3 is an end view taken along line 3--3 of FIG. 2, showing thecircumference of the collar 14, the proximal part 4 in cross-section andthe internal channel 16 of the proximal part 4.

FIG. 4 shows an embodiment wherein the orifice 18 has been arranged sothat it has a shape and direction that directs a stream of cooling waterdirectly at the cutting head without the use of an intervening jet 21,as shown in FIG. 2. It follows that more than one orifice 18 may beprovided, in which case the orifices are arranged equidistantly aboutthe circumference of the collar 14. FIG. 4 also shows the collar 14extending beyond the root 22 of the distal part 11, forming a shoulder23 which lies in a plane perpendicular to the axis A, facing the cuttingtip 12 of the dental bur. The root 22 is advantageously formed as aconical or flared part of the distal part 11.

FIG. 5 shows a preferred embodiment of cutting tip 12 which presents asubstantially spherical working outer surface 26. Distal part 11 ispreferably removably secured in an axial port 30 in collar 14 with a setscrew 32. Set screw 32 preferably extends through a threaded, lateralset screw bore 34 in collar 14. This feature permits replacement of aworn cutting tip 12, without the expense of replacing the entire bur 1and its internal fluid channels 16 and 17. It is to be understood thatcutting tip 12 alternatively may be separated at any point betweencollar 14 and cutting tip 12, and removably connected with well knownmeans. The replaceable cutting tip may alternatively have a cylindricalshape as in FIG. 1.

I claim:
 1. An elongated liquid-cooled dental bur having a longdirection comprising a proximal part adapted to be inserted into a drivedevice connected with a source of cooling fluid, a distal part having acutting tip, a first channel in said proximal part fluidly communicatingwith said source of cooling fluid, at least one orifice extending fromsaid first channel directed at said cutting tip for directing a spray ofcooling liquid at said cutting tip, a collar radially extending fromsaid proximal part having a circumference, wherein said orifice isdisposed in said collar proximal to said circumference.
 2. Aliquid-cooled dental bur according to claim 1, wherein said collar hasan end surface disposed transversely to said long direction and facingsaid distal part, and said orifice is disposed in said end surface.
 3. Aliquid-cooled dental bur according to claim 1, wherein said proximalpart is shaped as an elongate cylinder, and said first channel is shapedas a central bore in said cylinder.
 4. A liquid-cooled dental buraccording to claim 3, wherein said proximal part has a facetsubstantially parallel with said long direction for rotationally lockingsaid bur in said drive device.
 5. A liquid-cooled dental bur accordingto claim 3, wherein said proximal part has a radial recess for axiallylocking said bur in said drive device.
 6. A liquid-cooled dental buraccording to claim 1, wherein said bur tip has a diameter no greaterthan 1.3 mm.
 7. A liquid-cooled dental bur according to claim 1, whereinsaid cooling fluid is composed substantially of water.
 8. Aliquid-cooled dental bur according to claim 1, wherein at least part ofsaid distal part is removably secured to said proximal part, for removaland replacement of worn cutting tips.
 9. A liquid-cooled dental buraccording to claim 1, wherein said distal part is removably secured tosaid collar, for removal and replacement of worn cutting tips.
 10. Aliquid-cooled dental bur according to claim 9, wherein said distal partfits into an axial bore in said collar and is secured in said axial borewith set screw means.
 11. A liquid-cooled dental bur according to claim1, wherein said cutting tip is substantially spherically shaped.
 12. Aliquid-cooled dental bur according to claim 10 wherein said cutting tipis cylindrical.
 13. A liquid-cooled dental bur according to claim 10wherein said cutting tip is substantially spherical.
 14. An elongatedliquid-cooled dental bur having a long direction comprising a proximalpart adapted to be inserted into a drive device connected with a sourceof cooling fluid, a distal part having a cutting tip, a first channel insaid proximal part fluidly communicating with said source of coolingfluid, at least one orifice opening from said first channel and directedat said cutting tip for directing a spray of cooling liquid at saidcutting tip, an expanded portion radially extending from said proximalpart having a circumference, wherein said orifice is disposed in saidexpanded portion proximal to said circumference.
 15. An elongatedliquid-cooled dental bur having a long direction comprising a proximalpart having a proximal part longitudinal axis and adapted to be insertedinto a drive device connected with a source of cooling fluid, a distalpart having a distal part longitudinal axis, an average radius and acutting tip, a first channel in said proximal part fluidly communicatingwith said source of cooling fluid, said first channel having alongitudinal channel segment substantially parallel with said proximalpart longitudinal axis and a lateral channel segment extending generallyradially beyond said average radius of said distal part through alateral channel containing structure, at least one orifice opening outof said lateral containing structure and directed substantially towardsaid distal part longitudinal axis for directing a spray of coolingliquid generally toward said cutting tip.